Means for replacing twyers in air-blast furnaces.



v v A. 1). 'LEDUG I MEANS roR REPLAGING TWYEBS m AIR BLAST runmcns.

ArPLmATmN FILED APR. 5, 1911.

Patented May 7, 1912.-

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MEANS FOR. REPLACING TWYBBS IN AIR BLAST FURNACES; APPLICATION IiLEDAPR. 5, 19 11.

' Patented May 7, 1912,

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, A. 1). LEDUG. I MEA NS FOB REPLACING TWYBBS IN AIR BLAST FURNACES.

APPLICATION FILED APR. 5, 1911.

Patented'May 7, 1912.

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MEANS FOR REPLACING TVVYERS IN AIR-BLAST FURNACES.

Specification of Letters Patent.

Patented May 7, 1912.

Application filed April 5, 1911-. Serial N 0. 619,075.

To all whom it may concern:

Be it known that I, ALFRED Diisinn LEDUc, a citizen of the Republic ofFrance, and resident of Rouen, France, have invented a new and usefulMeans for Replacing Twyers in Air-Blast Furnaces, which is fully setforth in the following specification.

The present invention has for its object to replace the twyers which inair-blast fur: naces conduct the air to isolated points in the fusionzone, by a continuous slot extending throughout-the entire periphery ofthe furnace at the same height as that at which the twyers are locatedthus distributing the air uniformly and regularly to every part of thefusion zone.

In air blast furnaces the air is admitted through twyers arranged atgreater or smaller distances from each other; the air thus reaches thefusion zone at points which are more or less close together and the partcomprised between two adjacent twyers receives less air at its middlethan at its extremities.

The invention which forms the object of the present patent seeks toobviate the defects arising from blowing at certain points in line withthe twyers by a blowing effected uniformly throughout the entireperiphery of the furnace. This object is attained by replacing thetwyers by a slot extending throughout the entire outer and inner surfaceof the furnace; this slot may be regarded as constituted by twyersarranged immediately side by side with the interme diate walls omitted.The combustion is thus maintained by a continuous sheet of air insteadof by jets of air which always impinge upon the same points. Thisarrangement insures a uniform supply of air at every point of the fusionzone while at the same time every part of the exterior of this zone isvisible.

Contrary to what is the case in a known form of cupola furnaces in whichthe air is drawn through a circular slot and in which the pressurecannot exceed 10 to 50 mm. of water, the inventor surrounds the singlet-wyer, that is to say the slot, with an air chamber from which the airis forced into the fusion zone at the necessary pres sure for themetallurgical treatment that is to be carried out.

A movable screen composed of one or more independent parts arrangedinside the air chamber and operated from the exterior of this chamberenables the passage of the air to be reduced or cut off at any desiredpoint in the fusion zone; by reducing the passage of the air in thismanner it is possible to increase the pressure if necessary.

The sheet of air is applicable to all air blast furnaces whatever theform of these furnaces may be. This arrangement of blowing in a sheet ofair produces a more rapid fusion and perfect uniformity in the descentof the charges which results in an economy of fuel. It is a known factwith twyers that when the proportion of fuel is too small, chimneys areformed above the twyers through which the gases escape trap idly andthat through these chimneys the unfused materials reach the cruciblewhile between the twyers combustion is not complete owing to lack ofair. Consequently when blowing through twyers is adopted more fuel isburned than is really necessary in order to maintain above the twyersa'considerable thickness of fuel and this presents the double defect oflargely increasing the expenditure of fuel and diminishing the rapidityof the fusion.

An embodiment of the invention is illustrated by way of example in theaccompanying drawings in which Figure 1 is a front elevation partly insection. Fig. 2 is an end elevation partly in section. Fig. 3 is a planpartly in sect-ion through theupper water jacket, 5. Fig. 4 is 'asection on the axis of the inspection openings and through the lowerwater jacket 1. Fig. 5 is a semi-sectional end elevation showing theshutter 18.

Referring to the drawings in detail, there are two water jackets foreach face; the water jacket 1 rests upon cast iron plates 2 andcomprises a cold water inlet 3 and a communication chamber 1 dischargingthe water into the upper water jacket 5. The latter rests upon cast ironblocks 6 maintaining the water jackets 1 and 5 'at a uniform distanceapart; it has a hot water outlet at 7 The air chamber 8 containinginspection apertures 9 is secured to the water jackets 1 and 5; the airenters from the main conduit 10 through the nozzles 11 in the airchamber 8, passes between the water jackets 1 and 5 and enters thefurnace in the form of a sheet of air 12.

The water jackets 1 can be arranged in line with the water ackets 5 butit is preferable to set them back in order to prevent obstruction of thesheet of air 12 by the slag Which solidifies on the inner face of theWater j aeket.

The inspection apertures 9 enable the whole of the fusion zone to besupervised and the slot 12 to be freed by means of tongs if the passageshould by chance become obstructed by solidified slag.

According to circumstances but mainly for second-fusion cupola furnacesthe sheets of air can be multiplied by superposing other small ackets.

The thickness of the blocks 6 is variable according to the purposes forwhich the furnace is intended but during operation a shutter 18 in oneor more .parts enables the section of the slot 12 to be reduced by meansof the arm 19, the fixed part 20 and the nut 21.

In the application of the invention to a rectangular water jacketfurnace the sheet of air has been assumed to be adapted to each of thefour faces but, generally speaking it will only be applied to each ofthe two large faces or even to only one of them.

I claim:

In a blast furnace, a wall made up of upper and lower water jackets,said water jackets being spaced apart to provide an elongated horizontalpassageway or slit, such slit having substantially horizontal top andbottom walls, an air chamber arranged on the outside of the waterjackets and overlying said slit, a vertically disposed gate or valvearranged in said air chamber, outside of said Water jackets andextending substantially the full length of the slit, and means forraising and lowering said valve so as to regulate the amount of airpassing through said slit.

In testimony whereof I have signed this specification in the presence oftwo subscribing witnesses.

ALFRED DESIRE LEDUC.

Witnesses PAUL NonL, Cinovn.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. G.

